88 research outputs found
A Spin Modulated Telescope to Make Two Dimensional CMB Maps
We describe the HEMT Advanced Cosmic Microwave Explorer (HACME), a balloon
borne experiment designed to measure sub-degree scale Cosmic Microwave
Background anisotropy over hundreds of square degrees, using a unique two
dimensional scanning strategy. A spinning flat mirror that is canted relative
to its spin axis modulates the direction of beam response in a nearly
elliptical path on the sky. The experiment was successfully flown in February
of 1996, achieving near laboratory performance for several hours at float
altitude. A map free of instrumental systematic effects is produced for a 3.5
hour observation of 630 square degrees, resulting in a flat band power upper
limit of (l(l+1)C_l/2 pi)^0.5 < 77 microK at l = 38 (95% confidence). The
experiment design, flight operations and data, including atmospheric effects
and noise performance, are discussed.Comment: 4 pages, 3 figure
Overview and Status of the Laser Communication Relay Demonstration
NASA is presently developing first all optical high data rate satellite relay system, LCRD. To be flown on commercial geosynchronous satellite, it will communicate at DPSK and PPM modulation formats up to 1.244 Gbps. LCRD flight payload is being developed by NASA's Goddard Space Flight Center. The two ground stations, one on Table Mountain in CA, developed by NASA's Jet Propulsion Laboratory and another on Hawaiian island will enable bi-directional relay operation and ground sites diversity experiments. In this paper we will report on the current state of LCRD system development, planned operational scenarios and expected system performance
The Second Measurement of Anisotropy in the Cosmic Microwave Background Radiation at 0\fdg5 Scales near the Star Mu Pegasi
During the fifth flight of the Microwave Anisotropy Experiment (MAX5), we
revisited a region with significant dust emission near the star Mu Pegasi. A
3.5 cm low frequency channel has been added since the previous
measurement (\cite{mei93a}). The data in each channel clearly show structure
correlated with IRAS 100 \micron\ dust emission. The spectrum of the structure
in the 6, 9 and 14 cm channels is described by
, where = 1.3 and
= 19~K and is the Planck function. However, this model
predicts a smaller amplitude in the 3.5 cm band than is observed.
Considering only linear combinations of the data independent of the best fit
foreground spectrum for the three lower channels, we find an upper limit to
CMBR fluctuations of at the
95\% confidence level. The result is for a flat band power spectrum and does
not include a 10\% uncertainty in calibration. It is consistent with our
previous observation in the region
CMB Telescopes and Optical Systems
The cosmic microwave background radiation (CMB) is now firmly established as
a fundamental and essential probe of the geometry, constituents, and birth of
the Universe. The CMB is a potent observable because it can be measured with
precision and accuracy. Just as importantly, theoretical models of the Universe
can predict the characteristics of the CMB to high accuracy, and those
predictions can be directly compared to observations. There are multiple
aspects associated with making a precise measurement. In this review, we focus
on optical components for the instrumentation used to measure the CMB
polarization and temperature anisotropy. We begin with an overview of general
considerations for CMB observations and discuss common concepts used in the
community. We next consider a variety of alternatives available for a designer
of a CMB telescope. Our discussion is guided by the ground and balloon-based
instruments that have been implemented over the years. In the same vein, we
compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the
South Pole Telescope (SPT). CMB interferometers are presented briefly. We
conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and
Planck, to demonstrate a remarkable evolution in design, sensitivity,
resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1:
Telescopes and Instrumentatio
Treatment of poorly differentiated neuroendocrine tumours with etoposide and cisplatin
The purpose of this study was to evaluate by a retrospective analysis of 53 patients the efficacy of chemotherapy combining etoposide and cisplatin in the treatment of neuroendocrine tumours. The regimen was a combination of etoposide 100 mg m–2 day–1 for 3 days and cisplatin 100 mg m–2 on day 1, given by 2-h intravenous infusion, administered every 21 days. Twelve patients had a well-differentiated and 41 a poorly differentiated neuroendocrine tumour. Toxicity of treatment was assessed in 50 patients and efficacy in 52 patients. Among the 11 patients with a well-differentiated tumour evaluable for tumoural response, only one (9.4%) had a partial response for 8.5 months. Forty-one patients with a poorly differentiated tumour showed an objective response rate of 41.5% (four complete and 13 partial responses); the median duration of response was 9.2 months, the median overall survival 15 months and the median progression-free survival 8.9 months. Haematological grade 3–4 toxicity was observed in 60% of the cases with one treatment-related death, digestive grade 3–4 toxicity in 40% and grade 3 alopecia was constant. No severe renal, hearing and neurological toxicities were observed (grade 1 in 6%, 14%, 72% respectively and no grade >1). We confirm that poorly differentiated neuroendocrine tumours are chemosensitive to the etoposide plus cisplatin combination. However, the prognosis remains poor with a 2-year survival lower than 20% confirming that new therapeutic strategies have to be developed. © 1999 Cancer Research Campaig
Quality of life assessment as a predictor of survival in non-small cell lung cancer
<p>Abstract</p> <p>Background</p> <p>There are conflicting and inconsistent results in the literature on the prognostic role of quality of life (QoL) in cancer. We investigated whether QoL at admission could predict survival in lung cancer patients.</p> <p>Methods</p> <p>The study population consisted of 1194 non-small cell lung cancer patients treated at our institution between Jan 2001 and Dec 2008. QoL was evaluated using EORTC-QLQ-C30 prior to initiation of treatment. Patient survival was defined as the time interval between the date of first patient visit and the date of death from any cause/date of last contact. Univariate and multivariate Cox regression evaluated the prognostic significance of QoL.</p> <p>Results</p> <p>Mean age at presentation was 58.3 years. There were 605 newly diagnosed and 589 previously treated patients; 601 males and 593 females. Stage of disease at diagnosis was I, 100; II, 63; III, 348; IV, 656; and 27 indeterminate. Upon multivariate analyses, global QoL as well as physical function predicted patient survival in the entire study population. Every 10-point increase in physical function was associated with a 10% increase in survival (95% CI = 6% to 14%, p < 0.001). Similarly, every 10-point increase in global QoL was associated with a 9% increase in survival (95% CI = 6% to 11%, p < 0.001). Furthermore, physical function, nausea/vomiting, insomnia, and diarrhea (p < 0.05 for all) in newly diagnosed patients, but only physical function (p < 0.001) in previously treated patients were predictive of survival.</p> <p>Conclusions</p> <p>Baseline global QoL and physical function provide useful prognostic information in non-small cell lung cancer patients.</p
- …